layer via copy, duplicate layer 1, edit>transform>flip vertical,
duplicate layer 1 copy,

open teeth and paste, i rename it as teeth, lower the opacity,
edit>transform>scale,
higher the opacity back to 100%, add layer mask, use brush tool
set foreground color to black and paint the edge of layer teeth,
click layer thumbnail, go to image>adjustment>black and white,
back to image>adjustment>brightness/contrast set to brightness -63, contrast to 100
back to image >adjustment>color balance set midtones only cyan -23, blue +4
back to image>adjustment>selective color, set color to black,black to +100
back to image>adjustment>levels i set black to 54 and white to 222
duplicate layer 1, edit>transform>warp,
bring (layer 1) above the (layer 1 copy 3),add layer layer thumbnail,
paint the edge of the layer with soft brush

click (layer 1 copy 2), edit>transform>scale and warp,
and drag to allign with(layer 1 copy 3),
bring (layer 1 copy) above the (layer 1 copy 2)
edit>transform>warp,apply,warp it again,
add layer mask, warp it again focus allign on teeth,

merge(layer 1 copy) and (layer 1 copy 2), add layer mask
first paint with hard brush the eye and nose,
set foreground color to white, use soft brush,
start painting on top of the hole.

use dodge and burn tool

merge all layer except black BG,
create new layer below and paint black on the back of eye and nose of the skull
and merge layer rename it skull.
Creating shadow:
right click skull layer>select pixels,
1.make new layer above the skull layer, fill the selection with black
hit (ctrl+d), moved it to the left side of the skull.
2-3.click rectangular marquee tool, select half of the shadow,
right click>layer via cut, hit (ctrl+t) free transform,
right click select skew,
4.merge layer 1 and layer 2, rename it shadow.

go to filter>blur>gaussian blur i set to 7.0,
duplicate shadow layer, add layer mask,
paint the edge of the shadow on the top and merge,

duplicate skull layer,
hit (ctrl+T) free transform>flip vertical, bring it to below the skull
lower the opacity to 60%
add layer mask, paint with black on the edge of the reflection, using soft big brush.

layer via copy from the source image and paste, i use this layer as BG,
use rectangular marquee tool select half of the image, hit (ctrl+t) transform.

duplicate layer, filter>blur>gaussian blur
add layer mask paint with black the lower edge of the background.